BOSTON (CBS) – A probationary Boston firefighter allegedly caught buying heroin while on duty is off the job and facing charges.

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The Suffolk County District Attorney’s Office says Stephen Hogan, 24, was arrested Tuesday evening after Boston Police officers from the Drug Control Unit witnessed him buying a bag of heroin in the area of Columbus Avenue and Bray Street.

Hogan, of Dorchester, has since resigned from the Boston Fire Department, according to Boston Fire spokesperson Steve MacDonald. He served less than a year with the department.

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“It makes me angry,” said Mayor Tom Menino, “because the public trusts the firefighters, they trust them with our safety. There’s no place for something like this, with any of our public employees.”

Hogan is set to be arraigned on Thursday in Roxbury District Court for Possession of a Class A Drug (Heroin).

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Hogan is the son of Boston Fire District Chief Gerard Hogan.